(not applicable)
1. Field of the Invention
The instant invention pertains generally to the field of electrowinning. More particularly, the invention describes a method and apparatus for removing growth such as dendrite growth from electrodes during the electrowinning process.
2. Description of Related Art
There are many instances where metal is dissolved in a solution and it is desired to reclaim the metal from the solution. In the process of electrowinning metals from solutions, metals from a solution in an electrolytic or electrochemical cell grow dendrites or mossy growth of metal layers resulting in porous and uneven deposits that span the interelectrode gap. In other words, dendrites typically grow very rapidly from cathode to anode causing a short circuit of the cell. Various techniques have been used to overcome this problem including the use of centrifugal motion of a cathode within electrolyte to cause the dendrite growth to fall off as shown in U.S. Pat. No. 4,715,934 by Pentti Tamminen. In another technique, posts used in a reciprocating agitator cause a high velocity flow of slurry between the posts and electrode causing a scrubbing action as shown in U.S. Pat. No. 4,100,042 by Wojcik, et al. Although these methods are effective in removing dendrite growth, they require many moving parts or require significant maintenance. Additionally, some of these techniques are not suitable for electrolytic cells that have fairly narrow gaps or that have a significant number of electrodes.
In a first aspect of the present invention, a method of removing growth from an electrode during an electrowinning process includes the steps of placing a scraper between a first electrode and a second electrode of opposing polarity and moving the scraper a minimal distance relative to the electrodes.
In another aspect of the present invention, an electrolytic cell has a plurality of electrodes of opposing polarity and a scraper placed between each of the plurality of electrodes of opposing polarity. The scraper is arranged to move a minimal distance relative to the plurality of electrodes.